<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Flexbox Layout Example</title>
<link rel="stylesheet" href="styles.css">
</head>
<body>
  <div class="container">
    <div class="row align-start">
      <div class="item">Item 1</div>
      <div class="item">Item 2</div>
      <div class="item">Item 3</div>
    </div>
    <!-- 可以根据需要添加更多的行和列 -->
  </div>
</body>
</html>